Generalised Anxiety Disorder Assessment (GAD-7)

The Generalised Anxiety Disorder Assessment (GAD-7) is a brief measure for symptoms of anxiety, based on the generalised anxiety disorder diagnostic criteria described in the Diagnostic and Statistical Manual of Mental Disorders (DSM). The GAD-7 assessment asks patients to evaluate their level of symptoms over the last two weeks. When administered on multiple occasion at the start, middle and end of treatment, responses can be used to track treatment progress over time.

Given the simple language used in the assessment it is appropriate for individuals as young as 14 years. When used as a screening tool, further evaluation is recommended when the score is 10 or greater.

Using a cut-off score of 10 the GAD-7 can be used as a screening tool for three other common anxiety disorders – panic disorder (sensitivity 74%, specificity 81%), social anxiety disorder (sensitivity 72%, specificity 80%), and post-traumatic stress disorder (sensitivity 66%, specificity 81%) (Kroenke, et al. 2007).

Validity and Reliability

Lowe et al. (2008) investigated the validity and reliability of the GAD-7. Confirmatory factor analyses substantiated the 1-dimensional structure of the GAD-7. Internal consistency was identical across all subgroups (Cronbach’s alpha = 0.89). Intercorrelations with the PHQ-2 and the Rosenberg Self-Esteem Scale were r = 0.64 (p < 0.001) and r = -0.43 (p < 0.001), respectively. Women had significantly higher mean (SD) GAD-7 anxiety scores compared with men [3.2 (3.5) vs. 2.7 (3.2); p < 0.001]. Approximately 5% of subjects had GAD-7 scores of 10 or greater, and 1% had GAD-7 scores of 15 or greater.

Norms were developed by Stocker et al. (2021) with an Australian sample of 13,829 subjects (75.5% female). These norms were broken up by age:

• 18-29: Mean = 7.8, SD = 5.9
• 30-49: Mean = 6.6, SD = 5.4
• 50-69: Mean = 4.6, SD = 4.9
• 70+: Mean = 2.6, SD = 3.6

Scoring and Interpretation

A raw score (from 0 to 21) is presented as well as a percentile rank based on a normative community sample (Stocker et al., 2021) of age related peers.  A higher score indicates higher levels of anxiety symptoms. Percentiles are calculated according to the age of the client and provide a useful context for comparing a respondent’s results with a normative sample. A percentile of 50 represents typical (and healthy) patterns of anxiety, while higher percentiles represent higher levels of anxiety symptoms.  

A symptom severity description is presented based upon the raw score:

• 0-4 = None-Minimal
• 5-9 = Mild
• 10-14 = Moderate
• 15+ = Severe  

When the GAD-7 has been administered more than once, the graph of scores over time has a horizontal line at a score of 5, which is indicative of a mild anxiety level description.

Developer

Spitzer, R. L., Kroenke, K., Williams, J. B., & Löwe, B. (2006). A brief measure for assessing generalized anxiety disorder: the GAD-7. Archives of internal medicine, 166(10), 1092-1097.

References

Kroenke K, Spitzer RL, Williams JB, et al; Anxiety disorders in primary care: prevalence, impairment, comorbidity, and detection. Ann Intern Med. 2007:146(5):317-25.

Löwe, B., Decker, O., Müller, S., Brähler, E., Schellberg, D., Herzog, W., & Herzberg, P. Y. (2008). Validation and standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the general population. Medical care, 46(3), 266.